Science Grade 8 (2nd Quarterly Examination)

Crust

outermost layer of the earth

Mohorovicic Discontinouty

boundary line between the lower crust and upper mantle

mantle

larges layer

Gutenberg Discontinuity

line between lower mantle and outer core

core

central part of earth discovered by richard oldham

outter core

liquid layer

inner core

solid discovered by inge lehmann

lehmann discontinuity

line between outter core and inner core

Earthquake

shaking of the ground

focus

earthquake begins

epicenter

directly above the focus

fault

weak point

Tectonic earthquake

earths crust breaks due to geological forces

Explosion Earthquake

nuclear or chemical devices

Ricther Scale

Measured the magnitude

Collapse Earthquake

underground mines

seismograph

magnitude is measured using this

Normal Fault

pulling apart or extensional foces, hanging wall moves down to foot fault, form a valley

Strike-slip Fault

transcurrent fault, horizontal or sideways

eyewall

storms powerhouse

rainbans

arms of typhoon, group of clouds carrying rain and strong winds

Tropical Disturbance

Warm, moist air rises, creates low pressure